Process of converting cellulose and the like into sugar with dilute acids under pressure



1935- H. SCHOLLER ET AL 1,990,097

. v PROCESS OF CONVERTING CELLULOSE AND THE LIKE INTO SUGAR WITH DILUTE ACIDS UNDER PRESSURE '2 snets-sneet 1 Filed NOV. 29, 1930 INVENTOR 5 ATTORNEY Feb. 5, 1935.

H. SCHOLLER El AL PROCESS OF CONVERTING CELLULOSE AND THE LIKE INTO SUGAR WITH DILUTE ACIDS UNDER PRESSURE Filed Nov. 29, 1930 2 Sheets-Sheet 2 M MINVENTORS ATTORNEY Patented Feb. 5, 1935 UNITED STATES PATENT OFFICE 1,990,097 PROCESS OF CONVERTING CELLULOSE AND THE LIKE INTO SUGAR WITH DILUTE ACIDS UNDER PRESSURE Heinrich Scholler, Solln, near Munich, and Wal- In ermany December 9, 1929 26 Claims. (Cl. 127-37) It is known that cellulose can be converted into sugar by means of percolation under pressure with dilute acids.

According to the known method dilute acid is flowed continuously through the cellulose material during the pressure-heating. After a short time the sugar which has been formed is removed from the reaction chamber whereby it is protected against decomposition.

The aforementioned process yielded comparatively dilute liquors, the sugar content of which could not be increased much over 5-6% without loss of yield, even when compressed cellulose material and the counter-current principle were applied.

In accordance with the principles of the present process limited quantities of liquid are flowed through the cellulose material at fixed intervals (intermittently) during the heating at an elevated temperature and under pressure of several atmospheres. By this procedure more or less periodically the formed sugar is removed from the reaction chamber. The cellulose material is then, until the next batch of liquid arrives, in a moistened, wet or half-dry condition.

The movement of the batches of liquid is effected by displacing through vapours or gases. From the time of expulsion of one batch of liquid until the arrival of the next the cellulose material i under pressur e and, in a rnoreor less, moist conditioifferivelopedby.the gasfor vapour which is used for expulsion. The wetting liquid which stilladheres to"th"'cellulose material and which reacts acidly effects the continuance of the reaction. be natural to entertain fear that during the interruption of the flow decomposition should set in and render process disadvantageous, but this fear is not justified, for the raising of the flowing velocity of e imma es is"disadvanthe batc tztgewithout c ase of concen ra ion 0 MW lt isadvantageous'inthis' process "to'use compressed cellulose material and also to utilize the counter-current principle. The batches of liquid react when the counter-current principle is employed, the first with material which is most spent, and with the unspent material last. The counter-current principle can be carried throng in the single body with simultaneous feed of cel lulose and discharge of lignin, but practically it is simpler to use batteries connected in the counter-current.

It is also advisable to raise the temperatures during the process. A temperature of 1,50" 9.-

gressurewsteam or compressed gasesdlnitrogenc 17 ally suflices for the beginning, but

to accelerate the final reaction a temperature of 170 C.-l80 C. is preferred. When the graduation of temperature is applied simultaneously with the counter-current principle, a. drop in temperature occurs in the direction of the liquid 7 flowing through the system.

The pressing of the batches of liquid through the cellulose material can be effected in different ways. It is possible to pass means of its ownweight and its own steam pressure: in this case the movement of the liquid can also be accelerated through relief below the batch of liquid.

In a like manner the movement of batches of liquid and the transfer from one body into the other is effected when batteries are used. When the temperature is lowered, the vapour-pressure in the direction of the flow declines considerably. It is therefore possible to move the batches of liquid through the entire battery by means of their own steam-pressure.

effected with each single body. In this case it is advisable to cut out during the blowing-in, before the blast injection placed it, by a stop valve.

9 a es ca M99 The tia'issdrtauaa'er the liquid from one body to the other can also be effected by mechanical 3 propulsion by means of pumps and the like which are installed in the connecting piping-system of the bodies.

The batches of liquid can be introduced from the top and drawn off at the bottom and vice versa.

During the process the cellulose material is alternately in two different stages:

The first stage. the so-called flowing stage, is the condition during which a batch of liquid is forced through the material by means of steam or gas with comparatively great velocity, delivering the sugar formed.

The second stage, the quiescent stage, is the condition during which the liquid still adhering to the material, continuous to react on the cellulose, this taking place in the presence of the gases or vapours.

Both stages alternate, therefore the first stage returns, 1. e. a fresh batch of liquid is forced at 3 by, for example,

\rendering a bettermifl gn possible.

through the cellulose material by a new steam or gas column and delivers the sugar formed.

The accompanying drawings demonstrate examples of installing working plants to carry out the present process:

Fig. 1 shows a plant for the intermittent conversion into sugar in the single chamber and Fig. 2 shows a plant for the intermittent conversion into sugar according to the countercurrent-battery principle.

The arrangement shown in Fig. 1 consists of the hydrolisator 1, with acidproof bricklining, coppered and leaded and provided at its upper end with a valve '7 or some other device that can be manipulated to permit introduction of the cellulose material as well as with connections to admit hydw and steam, while at its lower en here is an opening also operative, to permit discharge of the lignin residue and a connecting branch for the delivery of the sugar liquor. At its lower cone, the hydrolisator is provided with an acidproof filter 2 which serves to separate the residue from the sugar liquor. The lower cylindrical part of the hydrolisator can be tapered a little as indicated the bricklining. The object of this is that towards the end of the process the lignin cake which shrinks and sinks to the bottom will better fill the lower part of the hydrolisator and cling firmly to the side walls, thus The hydrolisator also possesses a novel device for forcing in the cellulose material, and it consists of the container 4 with the pressure-piping and valve 5.

The cellulose material, introduced in either the dry or wet state into the silo or cyclone 40 by mechanical or pneumatic transportation, drops through the valve '1 into the hydrolisator 1. The container 4 is filled with steam under a pressure of a few atmospheres. As soon as the reactionchamber 1 is filled with cellulose material the valve '7 is closed and the steam-valve 5 opened quickly until the desired pressure is obtained in the hydrolisator 1. The steam (preferably saturated steam) pours through the wide piping and the widely opened valve 5 into the reaction-chamber l and instantly compresses the cellulose material into about a third of its original volume. It is not necessary to let the entering steam pass out at the lower end of the chamber 1, but the effect of compression is increased if the enclosed air and perhaps a little steam are allowed to escape through the valve 6 during the steam compression. It is essential for the success of the compression and for a rational working that piping and valve 5 are so constructed that as a consequence of the quick opening a sudden shock is exercised upon the cellulose material.

As the compression-operation is eifected in the course of a few seconds the consumption of steam is trifiing. The steam admitted condenses upon the cellulose material, warms it up and becomes in this way additionally useful.

After the compression has taken place the steam-inlet 5 is closed again. The cavity which has been produced by the compression of the cellulose material is refilled with fresh cellulose material from the silo 40, as previously described. After the valve 7 has been closed the mass is again compressed.

In this way the reaction chamber can, by several repetitions of steam compression and recharging, be almost completely filled with pressed cellulose material. The power of the compression depends upon the pressure used and on the adjustment of the valve 5 and can in this way be regulated at will. In place of pressure-steam,

pressure-water (liquor) or some other liquid may be used. Also in this case a suflicient quantity of liquid must suddenly enter the reaction cham-- ber 1, e. g. from an air-vessel. In this manner a strong compression can be achieved within a few seconds. Opening the valve 6 during the water-compression is favorable to the result. In an analogous manner, compression can also be secured upon more or less wet material by gases, e. g. air, nitrogen, carbonic acid.

In certain cases this compression of the material can also be effected by pumping the air out of the filled reaction-chamber and then suddenly introducing through the upper inlet valve a gaseous medium into the container.

The plant consists further of the small acid pump 9 and the big water pump 10 which are driven by the motor 12 coupled thereto, so that the proportion of the quantity of acid delivered and the quantity of water delivered is independent of the number of revolutions and the running time of the motor. The acid pump 9 is fed from the container 11 with strong acid, for example 40% sulphuric acid. It is best to operate the pumps only during lixiviation. The water pump 10 delivers water with a pressure of 15 atmospheres through the heat-exchange appliance 14. It is preheated by the liquor simultaneously flowing towards it. The hot water passes through the piping 15 to the steam-heater 16 which is with the steam trap 17. Here the previously preheated water is raised to the desired reaction temperature (160 C-195 C.) by means of live steam from the piping 28. Through the pipe 18 the hot water (160 C.-l95 C.) reaches the inoculation point 20 and is here mixed with the strong acid, which is delivered by means of the acid pump 9 through the piping 19. The concentration of the strong acid in container 11 and the proportion of delivery of the pumps 9 and 10 are so adjusted, that the resulting hydrolyzing liquid contains, for instance, 0.2% sulphuric acid or 0.1% hydrochloric acid.

The hydrolyzing liquid passes through the pipe 21 into the storage tank 22 and from here through the piping 23 (which is fitted with valves) to the distributor 24 and then flows through the hydrolisator 1. The storage-tank 22 has an electrical regulation device which stops the motor when a pressure of about 15 atmospheres has been reached and which, if desired, can regulate the number of revolutions of the motor even before that time.

The supply of live steam of about 15 atmospheres is carried out through the pipe 26 and the reducing valve 2'7. At the beginning of the reaction the steam pressure is reduced through this valve 27 to about '7 atmospheres, which corresponds to a temperature of 1 C. In the course of the process the pressure reduction is gradually removed, so that the pressure rises to 8, 9, 10 and finally to 15 atmospheres, corresponding to a temperature increase of 110 C.- 196 C.

From the steam piping 26 and behind the reducing valve 2'7 the steam pipes 28, 29 and branch off. The steam pipe 26 leads to the steam chamber 4. As previously mentioned, the steam pipe 28 serves to feed the heater 16. The steam piping 29 can be stopped and leads to the storage AND tank 22. The piping 30 which can also be stopped leads tothe hydrolisator 1.

After the hydrolyzing liquid has passed through the contents of the hydrolisator 1 and taken up the formed sugar, the sugar liquor passes through the filter 2 and through the valve 32 into the piping 33 and from here into the neutralisator 34 which is charged with gr uc le phosph ate. Here the weak acid of the sugar liquor becomes blunted and phosphoric acid and mono-calcium phosphate are taken up by the liquor. From here the blunted liquor passes through the piping 35 into the heat exchanger 14, passes off its heat to the fresh water meeting it and reaches, by way of the piping 36, the throttle valve 3'1 and hence the liquor container 38.

39 represents a portable drilling device, which after the finished process is inserted into the hydrolisator for the purpose of removing the lignin cake and which opens out in the inside of the hydrolisator in such a way that a quick and complete removal of the lignin is effected and a cleaning of the filter 2 rendered possible.

The periodical working method of the installation is as follows:

(1) Influa:.-Valves 29 and 23 are opened so that the batch of liquid which is contained in the tank 22 is forced into the hydrolisator through the pipe 23.

(2) Discharge.--After the storage-tank 22 has are closed and valves 31 and that the batches of liquid concerned leave the hydrolisator 1 and pass to the heat-exchanger 14 through the pipe 33. The opening of the throttle 37 is adjusted in such a way that the pressure before the throttle is only a little lower than the pressure in the pipe 30. The difference of pressure may, for instance amount to 1-2 atmospheres. During the time of discharge the pumps 9 and 10 are in operation and fill the storage tank 22.

By the arrangement described, especially the arrangement 22, it is made possible that fresh water and liquor flow simultaneously through the heat-exchanger l4, notwithstanding the fact that the inflow of the hydrolyzing liquid into the hydrolisator 1 and the outflow of the liquor from the hydrolisator do not take place at the same time.

(3) Resting time.-Aft er the quantity of liquid contained in the hydrolisator has flown off and the storage tank 22 has been filled with fresh hydrolyzing liquid a rest can take place during which the valve 23 remains closed and the valves entirely closed. During the time of rest the material wetted with hydrolyzing liquid is kept at temperatures from C.-195 0., according to the stage of the process, under corresponding steam pressures, so that the saccharification reaction continues undisturbed.

The limits set to the times of the inflow, outflow and the period of rest can be determined in different ways. The different periods may also overlap, for instance the discharge of the batch of liquid can begin before the inflow is quite finished. Also there may take place during the rest a certain outflow of liquor and finally the rest can be eliminated entirely and a batch of liquid can be introduced before the preceding one has left the hydrolisator.

Example 1 Arrangement-Experimental arrangement according to Fig. 1. Capacity of the hydrolisator 5000 ltr.

Used.--1000 kg. dry wood pulp. 10 ohm. water. 40 kg. 50% sulphuric acid (:10 ohm. 0.2%su1- phuric acid) 20 kg. crude phosphate.

Conditions of test Time of influx, discharge and rest amount to 10 minutes each. Total time of reaction 6 hours. 12 batches of liquid comprising about 800 ltr. are used. Temperature rising from to Yield.--With reference to the dry wood substance 50% reducing sugar, 50% fermentable sugar, 25 ltr. alcohol from 100 kg. dry wood substance.

Concentration of liquor Percent Reducing sugar 5 Fermentable sugar 4 Example 2 Instead of 0.2% sulphuric acid we use 0.1% hydrochloric acid. Otherwise the conditions of test remain the same. The yields are the same as those of Example 1.

Fig. 2 represents a counter-current battery plant. The installations for the preparation of the hydrolyzing liquid, the arrangements for the heat-exchange and the fitting-up of the hydrolisators are substantially the same as described and illustrated in Fig. 1. Fig. 2 represents a battery of eight bodies 41-48, each of which has a capacity of about 2000 liters. Each body can hold 500 kg. sawdust, if compressed, as well as about 1500 ltr. liquid. Body 41 contains the most spent material, the other bodies 42-46 constate of being emptied. with the pipe 49 through the stop valves 50. The connecting pipes 51 with the stop valves 52 lead from one body to the other, also from body 48 to body 41. The lower part of the connecting pipes 51 is connected to the discharge-piping 54 through the stop valves 53. The steamor gaspiping 55 leads to the upper part of the bodies through the stop valves 56. If necessary a steam compressor (heat tween valve 56 and the entrance into the reaction chamber, in order to make use of the exhaust steam. By means of the steam compressor (heat pumps) exhaust steam may also be taken from the piping 58 and the bodies 43 and 46 connected to it. The batches of liquid are first forced into the bodies through the distributing pipe 49 under pressure and pass (by steam pressure, for instance from the pipe 55) from one body to the next until they leave the battery through the stop valves 53 and the discharge piping 54. Through the discharge piping 54 the liquid reaches the coolingand cutting-off arrangement 59.

The steam (or the gases) contained, for the time being, in the bodies can be condensed or expelled by the liquid as it enters the body. The discharge valve 53 at the last body is best opened every time the batch of liquid enters, to be closed again after entry of the liquid. Opening and closing can be done by hand or automatically.

In the drawings the plant is represented at the moment when a batch of liquid of 1000 ltr. is contained in the body 41, as it is being transferred into the body 42. At the same time the preceding batch of liquid is being conducted from body 44 to body 45. Bodies 43 and 46 contain wetted material to which liquid adheres, and steam, and are in a state of rest. The temperatures in the bodies amount to about 195 C.- C. at a .declining rate, 1. e. the body with the nearly spent material has the highest temperatures.

Example 3 Arrangement.-Counter-current battery according to Fig. 2 and descriptions, accessories as in Fig. 1.

Used.-For each hydrolisator 500 kg. dry sawdust, 0.2% sulphuric acid.

Conditions of test Time of inflow 10 minutes.

Time of outflow 10 minutes.

No rest.

Time of reaction of each hydrolisator 6 to '7 hours.

Temperature 195 to C. declining in the direction of the flow.

Difference of temperature between each two bodies 5 to 7 C.

Quantity of liquid 750 ltr.

Proportion between total quantity'of pulp and total quantity of liquid 1:5.

At intervals of 1 hour each a. freshly filled body is connected on and a lixiviated body is disconnected. V

YieZds.-With reference to the dry wood subpine stance 49% reducing sugar resp. 39% fermentable sugar resp. 24.5 ltr. abs. alcohol. Concentration of liquor Percent Reducing sugar 8 Fermentable sugar '7 The hydrolyzing liquid reacting acidly may contain inorganic or organic acids, acid salts or combinations of these.

By the term cellulose or equivalent is meant all kinds of cellulose material, as wood, straw, reeds, peat, herbs, moss, etc.

The present process distinguishes itself from hitherto known particuthat the liquid does not flow continuously through the cellulose maliquid flow through it at intervals alternating with-periods of rest. While the formation of sugar takes place both during the rest and during the flow, the removal of the sugar takes place only during the period of flow.

This has the important advantage that the sugar can be removed with small batches of liquid that can be sent through the cellulose material comparatively quickly, in the same time as with the methods hitherto employed.

A correspondingly higher concentration of the sugar liquor is the consequence. On the other hand it is possible, by increasing the quantities of liquid and simultaneously raising the velocity of the how, to shorten the staying-time of the sugar so much that an increased yield results.

The liquor gained after this process contains small quantities of aldehyde and other substances that impede fermentation and render the utilization of the liquors and therefore the commercial exploitation of the process difficult, Furfurol and a little formaldehyde was found in the liquors. If no countermeasures are taken against the toxic effect of such substances fermentation is impeded. For instance, crude neutralized sugar-liquors which are produced by this process from pinewood ferment only slowly in spite of big doses of yeast and organic nitrogen. The detoxication of the liquors and the transformation into easily fermentable sugar in an economical manner is therefore part of the whole problem. The novelty of the method consists in the combination of different means, the manner of their application and the proportions of their quantities.

Experiments have shown that in pinewoodliquor certain minimum quantities of phosphoric and sulphurous salts and organic nitrogen must be contained. With reference to existing reducing sugar additions of 0.2 to 2.0% ric acid (P205) and 1-5% sulphurous acid (S02) and 0.5 to 5% nitrogen (N) are required. The requirements of nitrogen may be secured to the extent of A by inorganic nitrogen, but A must consist of organic nitrogen.

Liquors which already contain phosphoric acid, nitrogen and sulphurous acid in the proportions stated are with advantage brought to a pH of 5 to 6 with carbonate of lime and calcium hydroxide under stirring with air, and in this state they are easily fermentable.

Example 4 1000 ltr. pinewood-sugar liquor with a content of 50 kg. reducing sugar 1,5 kg. S02 0,375 kg. org. N 1,125 kg. inorg. N. 0,5 kg. P205 are brought to a pH of 5.6 by the addition, under stirring with air, of carbonate of lime and subsequent admixture of calcium hydroxide. The liquor thus prepared and to which 0.5 kg. yeast, which has preferably become used before to cellulose sugar liquor, is added, can be fermented in about a day. Fermentation is accelerated if the liquor is kept in motion. To carry out the fermentation process the well known influx-method is also suitable.

The mode of treatment is, however, dependent upon the kind of cellulose material. Combinations of different kinds of wood or combinations of wood with straw or rice husks have proved to be particularly advantageous. In this case the minimum figures for admixtures indicated above for pinewood have to be reduced.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is:-

1. The process of saccariflcation of cellulose which comprises maintaining cellulose material at elevated temperature and pressure and intermittently flowing dilute acid through the same at predetermined intervals to promote the saccharification reaction and remove the sugar between passages of acid, during which intervals the sacchariflcation reaction continues.

3. The process of saccharification of cellulose which comprises maintaining a batch of cellulose material at elevated temperatu e and pressure and intermittently flowing batches of dilute acid into and out of the batch of cellulose material at predetermined intervals to promote the sacchariflcation reaction and remove the sugar formed, the inflow of each batch of acid being started before the outflow of the preceding batch is completed, whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

4. The process of sacchariflcation of cellulose which comprises maintaining a batch of cellulose material at elevated temperature and pressure and intermittently flowing batches of dilute acid into and out of the batch of cellulose material at predetermined intervals to promote the saccharification reaction and remove the sugar formed, the outflow of each batch of acid being completed when the inflow of the succeeding batch is started, whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

5. The process of sacchariflcation of cellulose which comprises maintaining a batch of cellulose material at elevated temperature and pressure and intermittently introducing batches of dilute acid into the batch of cellulose material and withdrawing the same therefrom at predetermined intervals to promote the sacchariflcation reaction and remove the sugar formed, each batch of acid being introduced before a preceding batch is withdrawn, whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

6. The process of sacchariflcation of cellulose which comprises maintaining cellulose material at temperatures from C. to 220 C. under pressures of several atmospheres and intermittently flowing dilute acid through the same at predetermined intervals to promote the sacchariflcation reaction and remove the sugar formed, whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

'I. The process of sacchariflcation of cellulose which comprises maintaining cellulose material at elevated temperature and pressure, intermittently flowing dilute acid through the same at predetermined intervals to promote the sacchariflcation reaction and remove the sugar formed, and raising the temperature of the cellulose material during the process from an initial temperature of approximately C. to a flnal temperature of approximately C., whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

8. The process of sacchariflcation of cellulose which comprises maintaining cellulose material at elevated temperature and pressure, intermittently flowing dilute acid through the same at predetermined intervals to promote the sacchariflcation and remove the sugar formed, raising the temperature of the cellulose material during the process from an initial temperature of approximately 150 C. to a final temperature of approximately 195' C., and increasing the pressure on the cellulose material during the process from an initial pressure of approximately seven atmospheres to a final pressure of approximately fifteen atmospheres, whereby the cellulose material is left in a wet, moist or semi-dry state in the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

9. The process of sacchariflcation of cellulose which comprises maintaining cellulose material under saturated steam pressure of several atmospheres and intermittently flowing hot dilute acid through the same at predetermined intervals to promote the sacchariflcation reaction and remove the sugar formed, whereby the cellulose material is left in a wet, moist or semi-dry state during the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

10. The process of sacchariflcation of cellulose which comprises maintaining cellulose material under saturated steam pressure of several atmospheres, intermittently flowing hot dilute acid through the same to promote the sacchariflcation reaction and remove the sugar formed, and raising the steam pressure during the process from an initial pressure of approximately seven atmospheres to a final pressure of approximately fifteen atmospheres, whereby the cellulose material is left in a wet, moist or semi-dry state during the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

11. The process of sacchariflcation of cellulose which comprises intermittently flowing hot dilute acid through cellulose material at predetermined intervals and maintaining the said material under saturated steam pressure of several atmospheres during the intervals between passages of acid, whereby the sugar formed is removed and the cellulose material is left in a wet, moist or semi-dry state during the intervals between passages of acid, during which intervals the sacchariflcation reaction continues.

12. The process of sacchariflcation of cellulose which comprises intermittently flowing hot dilute acid through cellulose material at predetermined intervals and maintaining the said material at elevated temperature and pressure during the intervals between passages of acid, whereby the sugar formed is removed and the cellulose material is left in a wet, moist or semi-dry state during the intervals between passages of acid, during which intervals the reaction continues.

13. The process of sacchariflcation of cellulose which comprises maintaining a quantity of cellulose material consisting of progressively less spent consecutive portions at elevated temperature and pressure, intermittently flowing dilute acid through the same at predetermined intervals, whereby the acid flows through the most spent portion first and the remaining portions in order, and intermittently removing the most spent portion from the quantity of cellulose material being treated and adding a fresh portion.

14. The process of sacchariflcation of cellulose which comprises maintaining a quantity of cellulose material consisting of progressively less spent consecutive portions at elevated temperature and pressure, intermittently flowing batches of dilute acid through the same at predetermined intervals, each batch being flowed through the most spent portion first and the remaining portions in order and introduced before the withdrawal of a preceding batch, and intermittently removing the most spent portion of cellulose material from the quantity being treated and adding a fresh portion.

15. The process of sacchariflcation of cellulose which comprises maintaining a quantity of cellulose material consisting of progressively less spent consecutive portions at elevated temperature and pressure, intermittently flowing batches "of dilute acid through the same at predetermined intervals, each batch being flowed through the most spent portion first and the remaining portions in order and withdrawn before the introduction of a succeeding batch, and intermittently removing the most spent portion of cellulose material from the quantity being treated and adding a fresh portion.

16. The process of sacchariflcation of cellulose which comprises maintaining a body of cellulose material consisting of progressively less spent consecutive cross-sectional portions at elevated temperature and pressure, intermittently flowing dilute acid through the same at predetermined intervals, whereby the acid flows through the most spent portion first and the remaining portions in order, and intermittently removing the most spent portion of the cellulose material being treated and adding a fresh portion.

17. The process of saccharification of cellulose material which comprises maintaining a body of cellulose material at elevated temperature and pressure, flowing a quantity of dilute acid into the body of cellulose material, maintaining a second body of less spent cellulose material at elevated temperature and pressure, flowing the liquid from the first-mentioned body into the second body of cellulose material, whereby the material of the first body is left in a wet, moist or semidry condition at elevated temperature, flowing the liquid out of the second body of cellulose material, whereby it is left in a wet, moist or semidry condition at elevated temperature and pressure, and flowing a second quantity of dilute acid into the first batch of cellulose material.

18. The process of sacchariflcation of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material, flowing a quantity of dilute acid successively through each body of cellulose material in the series starting with the one most spent, similarly flowing a second quantity of dilute acid successively through each body in the series at predetermined intervals after the passage of the first-mentioned quantity of dilute acid, and maintaining each body of cellulose material at elevated temperature and pressure between passages of dilute acid, whereby the material in each body is maintained in a wet, moist or semi-dry state at elevated temperature and pressure for a predetermined period of time before passage of a quantity of dilute acid therethrough.

19. The process of sacchariflcation of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material at elevated temperature and pressure, flowing a quantity of dilute acid successively through each body of cellulose material in the series starting with the one most spent, and similarly flowing a second quantity of dilute acid successively through each body in the series at predetermined intervals after the passage of the first-mentioned quantity of dilute acid, whereby the material in each body is maintained in a wet, moist, or semidry state at elevated temperature and pressure for a predetermined period of time before passage of a quantity of dilute acid therethrough.

20. The process of saccharification of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material under high pressure and at temperatures ranging from approximately 195 C. in the most spent body of cellulose material to approximately 140 C. in the least spent body, and intermittently flowing the sacchariflcation batches of dilute acid successively through each body in the said series, starting with the one most spent at predetermined intervals, whereby each body of cellulose material is maintained in a wet, moist or semi-dry state during the intervals between passages of acid.

21. The process of sacchariflcation of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material under saturated steam pressures ranging from approximately fifteen atmospheres on the most spent body of cellulose material to approximately seven atmospheres on the least spent body, and intermittently flowing batches of dilute acid successively through each body in the said series, starting with the one most spent, at predetermined intervals, whereby each body of cellulose material is maintained in a wet, moist or semidry state during the intervals between passages of acid.

22. The process of sacchariflcation of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material in suitable containers under progressively decreased elevated saturated steam pressures with the highest pressure on the most spent body of material and the lowest pressure on the least spent body of material, flowing a batch of dilute acid into the first container containing the most spent cellulose material, flowing the said batch of liquid into the second container by means of the difference in pressure between the first and second containers, flowing the said batch of acid into the third container by means of the difference in pressure between the second and third containers and forcing a' second batch of dilute acid into the first container by means of saturated steam at the highest pressure, flowing the first-mentioned batch of acid into the fourth container by means of the difference in pressure between the third and fourth containers and flowing the second batch of acid into the second container by means of the difference in pressure between the first and second containers, and flowing each batch of acid in its turn out of the last container by means of the pressure therein, all of the saturated steam used in the process being added to the system through the first container with each fresh batch of dilute acid added.

23. The process of saccharification of cellulose which comprises maintaining a series of progressively less spent bodies of cellulose material, intermittently passing batches of hot dilute acid successively through each body in the said series, starting with the one most spent, at predetermined intervals, and maintaining each body during the intervals between passages of acid under saturated steam pressure ranging from approximately fifteen atmospheres on the most spent body to seven atmospheres on the least spent body.

24. The process of saccharification of cellulose which comprises compressing cellulose material by means of a sudden increase in pressure on the said cellulose material, maintaining the said compressed cellulose material at elevated temperature and pressure and intermittently flowing dilute acid through the same to promote the saccharification reaction and remove the sugar formed, whereby the cellulose material is left in a wet, moist or semi-dry state during the intervals between passages of acid, during which intervals reaction continues.

25. The process of saccharification of cellulose 7. Slltims, m,

AND UAhBuiiYDRATES.

which comprises compressing cellulose material by means of a sudden downward increase in by means of a sudden downward increase in presgaseous pressure on the said cellulose material, sure on the said cellulose material, maintaining maintaining the said compressed cellulose mathe said compressed cellulose material at elevated terial at elevated temperature and pressure and temperature and pressure and intermittently intermittently flowing dilute acid through the flowing dilute'acid through the same to promote same to promote the saccharlfication reaction and the saccharification reaction and remove the remove the sugar formed, whereby the cellulose sugar formed, whereby the cellulose material is material is left in a wet, moist or semi-dry state left in a wet, moist or semi-dry state during the during the intervals between passages of acid, 10 intervals between passages of acid, during which during which intervals the saccharification reintervals the saccharification reaction continues. action continues.

26. The process of saccharification of cellulose which comprises compressing cellulose material HEINRICH SCHOLLER, WALTER KARSCH. 

